decade after instituting pioneering policies on clergy sexual abuse, Fall River Bishop Sean Patrick O'Malley was named by Pope John Paul II yesterday to lead a Florida diocese whose two previous bishops resigned after admitting that they had molested boys.

O'Malley, 58, a rising star once considered a possible successor for the late Cardinal John O'Connor in New York, is scheduled to be installed as bishop of the sprawling Palm Beach Diocese on Oct. 19. The announcement appears to match O'Malley's experience in the devastating aftermath of the James Porter sex abuse case with a pastoral emergency in Florida that has angered parishioners in five counties.

''The whole church feels the pain of this scandal,'' O'Malley said at a Florida news conference, ''and is anxious to try to bring some healing and reconciliation to our families and communities that have been so shaken by these sad events and by the mishandling of these situations on the part of the church.''

O'Malley's appointment will fill the vacancy created March 8 when Bishop Anthony J. O'Connell, 63, resigned after admitting that he had fondled a teenage student at a Missouri seminary in the 1970s. O'Connell's decision quickly followed a newspaper report of the allegation, and came one day after he and nine other bishops had issued a statement denouncing sex abuse by the clergy as ''criminal and sinful.''

O'Connell's predecessor, Palm Beach Bishop J. Keith Symonds, resigned in 1998 after he admitted that he had molested five altar boys.

''Reconciliation always demands a firm purpose of amendment,'' O'Malley said at the Cathedral of St. Ignatius of Loyola in Palm Beach Gardens, Fla. ''It means seeking new ways to avoid the grave mistakes of the past and to make the safety of children our paramount goal.''

The Palm Beach Diocese has a Catholic population of 246,000, compared with 400,000 in the Fall River jurisdiction, which includes Cape Cod and the islands.

O'Malley, a Franciscan priest who became bishop of Fall River in 1992, was lauded yesterday for his bridge-building work following the Porter case. The former Massachusetts priest pleaded guilty in 1993 to molesting 28 children and was sentenced to 18 to 20 years in prison.

''I think the world of Bishop O'Malley,'' said lawyer Roderick MacLeish Jr., who represented 101 clients in the Porter case and currently has more than 200 clients who contend they were sexually abused by priests in the Boston Archdiocese. ''He sat down face to face with the victims of James Porter in a variety of ways. ... He's an incredibly compassionate human being, very humble, extremely modest. It's a terrible loss for Fall River.''

As part of the Fall River Diocese's settlement with Porter's victims, O'Malley was instrumental in establishing a system in which abuse allegations were referred to a social worker outside the church. An independent review board, which included mental-health professionals and legal specialists, would consider the allegations and recommend treatment for the victim and possible criminal action against the priest.

Mandatory reporting to civil authorities was instituted for any allegation of abuse of a minor. In addition, the diocese paid for treatment and medication for Porter's victims, said diocesan spokesman John Kearns.

MacLeish said that the Fall River model, which borrowed from a Chicago system developed under Cardinal Joseph Bernadin, was likely the second of its kind in the United States. In the last decade, the model has been copied extensively, MacLeish said.

In 1995, O'Malley required that any priest, seminarian, church employee, or volunteer with access to children participate in abuse prevention workshops, complete a detailed questionnaire on their past, and agree to a criminal background check, Kearns said.

O'Malley faces a daunting challenge to win the trust of new parishioners who have been shell-shocked by the sex-abuse scandal, said Ed Ricci, a lawyer and practicing Catholic in West Palm Beach, Fla.

''Although our faith in the doctrines of Christianity and Catholicism are not shaken, we're demoralized,'' said Ricci, a church fund-raiser who added that he does not know much about O'Malley. ''This is an issue of basic morality and basic human decency. The laity in this diocese ... have grave misgivings in placing their trust in the hierarchy of this diocese.''

O'Malley, who often wears the brown robe and sandals customary for his Franciscan order of Capuchins, will continue to serve in Fall River until his installation in Palm Beach. Before his transfer to Fall River, O'Malley served as bishop in St. Thomas, the US Virgin Islands. Throughout his career, he has expanded outreach and services for minorities, particularly Brazilian, Haitian, and Hispanic parishioners.